Background. Although whole-organ gene transfer has been reported in heart and liver transplant models, it has not been well characterized in lung grafts. The aim of this study was to determine the feasibility of ex vivo gene transfer to rat lung isografts during cold preservation using an adenoviral vector. Methods. F344 rats, divided into four groups, underwent orthotopic left lung transplantation. In group I, lung grafts were flushed with adenovirus carrying the β-galactosidase gene. After storage at 10°C, grafts were implanted in recipient animals. Group II underwent the same procedure but graft storage was at 4°C. Groups III (10°C) and IV (4°C) served as controls. On postoperative day 5, recipients were sacrificed, and native and transplanted lungs were examined. Results. In group I, all animals showed successful, albeit patchy, gene expression. This occurred in 2 of 4 animals in group II, the other 2 showing no expression. Transduced cells were consistent morphologically with endothelial cells and pneumocytes. A minimal mononuclear inflammatory infiltrate was present. Control groups showed no transduction. Conclusions. It is feasible to perform ex vivo adenoviral- mediated gene transfer to rat lung isografts during cold preservation.